The basic K nuclear cluster K- pp and its enhanced formation in the p + p -> K+ + X reaction

Abstract

We have studied the structure of K- pp nuclear cluster comprehensively by solving this three-body system exactly in a variational method starting from the Ansatz that the Lambda(1405) resonance (Lambda*) is a K-p bound state. We have found that our original prediction for the presence of K-pp as a compact bound system with M = 2322$MeV/c2,B=48MeVandGamma=60MeVremainsunchangedbyvaryingtheKba-rNandNNinteractionswidelyasfarastheyreproduceLambda(1405).ThestructureofK-pprevealsamolecularfeature,namely,theK-inLambda\ast asan"atomiccenter"playsakeyroleinproducingstrongcovalentbondingwiththeotherproton.Wehaveshownthattheelementaryprocess,p+p->K++Lambda\ast +p,whichoccursinashortimpactparameterandwithalargemomentumtransfer(Q1.6$ GeV/c), leads to unusually large self-trapping of Lambda* by the participating proton, since the Lambda*-p system exists as a compact doorway state propagating to K- pp (R{Lambda*-p} ~ 1.67 fm).

Comments: 18 pages, 14 figures. Phys, Rev. C, in press